get_dom_mutation_delta

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

No annotations exist, so the description carries the burden of behavioral disclosure. It explains that the tool returns added and removed elements and highlights the efficiency benefit. However, it does not mention error handling, prerequisites (e.g., valid trace/action index), or limitations (e.g., ARIA tree availability), leaving meaningful gaps.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

Two concise sentences with no redundant wording. The first sentence leads with the core action, and the second explains the value proposition. Every phrase adds information.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

The description adequately covers purpose and return value for a diff operation. It does not include an output schema, but explains what is returned. The parameter description already references get_action_timeline for obtaining action_index, so the tool description remains sufficiently complete for an agent to invoke it correctly.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100% and both parameters (trace_path, action_index) have detailed descriptions. The tool description adds no extra semantic information about parameters, so the baseline score of 3 applies.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

Description uses a specific verb 'Diffs' and identifies the resource 'ARIA tree' with a clear scope 'before and after a specific action'. This distinguishes it from sibling tools like get_aria_accessibility_tree (full tree snapshot) and compare_traces (whole trace comparison).

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description gives clear context for when to use the tool: when the agent needs to see exactly what changed after an action without comparing full DOM dumps. It implies the use case but does not explicitly name alternatives or state when not to use it, so it falls short of a 5.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.